Strings

1
Strings

• Includes
• include ltstdio.hgt
• include ltstdlib.hgt / needed by atoi( )
  and atof( ) /
• include ltstring.hgt / needed by str...(
  ) functions /

2
Copy One Array to Another

• / assign a to b /
• strcpy( b, a )
• printf( "s\n", b )

3
Add One Array to Another

• strcpy( b, a )
• strcat ( b, " " )
• strcat ( b, a )

4
Compare Strings

• / "Gary Burt" comes before "Mike Burt", so
  print a negative number /
• printf( "d\n", strcmp( a, c ) )
• / "Mike Burt" comes before "Gary Burt", so
  print a positive number /
• printf( "d\n", strcmp( c, a ) )
• / "Gary Burt" is the same as "Gary Burt", so
  print zero /
• printf( "d\n", strcmp( a, "Gary Burt" ) )

5
Getting Words From a String

• / get the first token (delimited by a blank) /
• printf( "s\n", strtok( b, " " ) )

6
Convert String to Numeric

• / convert a string to an integer /
• printf( "d\n", atoi( "1234" ) )
• / convert a string to a float /
• printf( "f\n", atof( "1234.5678" ) )

7
Find Length Of A String

• printf( "b is d characters long\n", strlen( b )
  )

8
Sample Program

• include ltstdio.hgt
• include ltstdlib.hgt / needed by atoi( ) and
  atof( ) /
• include ltstring.hgt / needed by str...( )
  functions /
• int main( void )
• char a 100 "Gary Burt"
• char b 100
• char c 100 "Mike Burt"
• / Make sure the array a is as expected /
• printf( "s\n", a )

9
Sample Program

• / assign a to b /
• strcpy( b, a )
• printf( "s\n", b )
• / put in a space and add the array a to what
  is in array a /
• printf( "b is d characters long\n", strlen(
  b ) )
• printf( "s\n", b )
• strcat ( b, " " )
• printf( "b is d characters long\n", strlen(
  b ) )
• printf( "s\n", b )
• strcat ( b, a )
• printf( "b is d characters long\n", strlen(
  b ) )
• printf( "s\n", b )

10
Sample Program

• / "Gary Burt" comes before "Mike Burt", so print
  a negative number /
• printf( "d\n", strcmp( a, c ) )
• / "Mike Burt" comes before "Gary Burt", so
  print a positive number /
• printf( "d\n", strcmp( c, a ) )
• / "Gary Burt" is the same as "Gary Burt", so
  print zero /
• printf( "d\n", strcmp( a, "Gary Burt" ) )
• / get the first token (delimited by a blank)
  /
• printf( "s\n", strtok( b, " " ) )

11
Sample Program

• / convert a string to an integer /
• printf( "d\n", atoi( "1234" ) )
• / convert a string to a float /
• printf( "f\n", atof( "1234.5678" ) )
• return 0

12
Output

• Gary Burt
• Gary Burt
• b is 9 characters long
• Gary Burt
• b is 10 characters long
• Gary Burt
• b is 19 characters long
• Gary Burt Gary Burt
• -1
• 1
• 0
• Gary
• 1234
• 1234.567800